Interlocking electrical connectors



p 1965 w. w. DE VORE, JR 3,206,709

INTERLOCKING ELECTRICAL CONNECTORS Filed Aug. 12, 1963 INVENTOR. mi/x i flaw BY 7 M M IZTIWRNEYS.

United States Patent M 3,206,709 INTERLOCKING ELECTRICAL CONNECTORS William W. De Vore, .lr., Palos Verdes Estates, Calif, assignor to Harvey Hubbell, Incorporated, Bridgeport, Comp, a corporation of Connecticut Filed Aug. 12, 1963, Ser. No. 301,314 4 Claims. (Cl. 339-91) This invention relates to an electrical wiring device of the type employed for making detachable electrical cable connections. More particularly, the invention relates to such wiring devices having interlocking means for preventing the accidental separation of the connector parts.

Interlocking electrical connectors customarily comprise a pair of connecting parts, a male part and a female part. Each part carries electrical contacts that engage each other when the parts are longitudinally moved together, thereby completing an electrical connection. The electrical contacts on one of the parts are designed to interlock with one or more portions of the other part when the parts are rotated relative to one another after having been connected. Connectors of this type require the manual rotation of one part relative to the other in order to actuate the interlocking means. It has been proposed to incorporate into the female connector a resilient means arranged to automatically act on one or more of the electrical contacts of the male connector so that, after the parts are moved longitudinally together sufiiciently to make electrical connection, they are automatically rotated to effect interlocking. A device of this kind is illustrated and claimed in U.S. Patent 3,066,276, which issued on November 27, 1962, to Harvey Hubbell et al. The connector disclosed in that patent has a number of important advantages over those known in the prior art. However, it will be noted that, in that device, a leaf spring or a spring-loaded cam is employed which bears laterally against a shouldered blade while it is being inserted into the female part. When the shoulder of the blade has cleared the front Wall of the female part, it is displaced laterally automatically to effect locking. Accordingly, the patented connector requires that the male contact part move longitudinally against the lateral resistance offered by the spring or cam for a substantial portion of its travel.

It is the primary object of the present invention to provide an improved automatically self-locking electrical connector wherein the contacts of the male part do not engage the locking means actuator until the contacts near the limit of their longitudinal travel.

Other objects are to provide such a connector which is simple in construction, inexpensive to manufacture, and reliable in usage.

The manner in which the foregoing objects are achieved will be more apparent from the following description, the appended claims, and the figures of the attached drawing wherein:

FIG. 1 is an elevational view of the two main parts of an interlocking electrical connector which incorporates this invention;

FIG. 2 is an enlarged cross-sectional view taken substantially along the line 22 of FIG. 1;

FIG. 3 is an enlarged cross-sectional detail view taken substantially along the line 33 of FIG. 2;

FIG. 4 is similar to FIG. 3 but illustrates a condition during the sequence of operation; and

FIG. 5 is a cross-sectional detail View taken substantially along the line 5-5 of FIG. 2.

The objects of this invention are achieved by means of an interlocking electrical connector including an insulating body portion defining a plurality of chambers and a front wall on the body portion defining a plurality of spaced openings. Each of the openings communicates lilfififlfiil Patented Sept. 14, 1965 with a diiferent one of the chambers. A female electrical contact is positioned within each chamber to receive a male contact blade inserted through the corresponding opening. A blade positioning element is mounted within one of the chambers and is spaced from the corresponding female contact. The positioning element is spring biased to urge the blade positioning element against a blade to cause lateral displacement of the blade. Latching means are also provided to retain the blade positioning element out of contact with the blade until the blade has been inserted into the body portion by a predetermined amount.

Reference to the figures of the drawing will indicate that the invention has been illustrated as incorporated into a connector body and connector cap assembly. How ever, it will be understood that the invention is equally adapted for incorporation into other types of electrical cable or cord connectors; for example, electrical receptacles and attachment plugs.

In FIG. 1 there is illustrated an electrical connector incorporating the present invention and including an electrical cap 10 and a connector body 12. The connector body 12 icludes a main body portion 14, molded of a known suitable electrical insulating plastic material, which is seated partially within a metallic shell 16 and secured thereto by means of screws 17. The cap Ill and connector body 12 are each provided with a cable grip clamp 18 arranged to grip a respective end of the cables 20, 22. Extending from the cap 10 are a pair of male contact blades 24. Each of blades 24 is rigidly secured to the usual body 11 of plastic material forming a part of cap 10 and electrically connected to the conductors of cable 22 by suitable terminal means which are not shown but are well-known in the art. The blades 24 extend longitudinally outwardly from the cap 10 and are diametrically positioned relative to the longitudinal axis of the cap. The end of each of male contact blades 24 includes a laterally extending lug portion 26 which forms a locking shoulder 28 on each of the blades 24.

The main body portion 14 of connector body 12 includes a slotted front wall 30 for receiving male blades which, together with the remainder of the body portion 14, defines a cavity 32 enclosing one female contactterminal assembly 34 and a cavity 36 enclosing another female contact-terminal assembly 38. The assemblies 34, 38 are of the spring clip contact type which are well known in the art. The main body portion 14 is formed in such a fashion that the walls of the cavities 32, 36 define recesses positioned longitudinally of body 12 for receiving a pair of dielectric inserts 40, 42. The inserts 40, 42 are each positioned at the opposite side of a different one of the slots in front wall 349 from the respective assembly 34 or 38.

The dielectric insert 40 or 42 serves as the main structural support of the actuating mechanism for the locking means of this invention. The actuating mechanism is mounted Within the insert so that it is completely separable from the connector body 12 when the main body portion 14 is removed from the metallic housing 16. The entire insert may thus be removed and replaced at will as a unit without alfecting the electrical characteristics and operation of the connector body.

The construction of the insert 40 and its contained mechanism is most clearly illustrated in FIGS. 2-5. As the insert 40 is the same as insert 42, the following description applies equally well to either insert. The insert 40 is constructed of a plastic material which is similar to that of body portion 14 and includes an elongated back wall 40a which is slightly curved on its outer surface as illustrated in FIG. '2 to conform to the curvature of an inner wall surface of recess 36 in main body portion 14. The end of insert 40 which is farthest removed from front wheel 30 includes an end wall 4011 which supports a short depending lip 400 which is inwardly spaced from and generally parallel to back wall a. Back wall 40a defines an elongated slot 44, and a smaller elongated slot 46 is provided in the lip 40c in alignment with slot 44. The back wall 40a is further provided with a stud 40d extending inwardly therefrom which carries a lateral finger 40c spaced from and parallel to the back wall 40a and defining a retaining grove 48 therebetween. The end of back wall 40a that is opposite the end wall 40b carries a metallic catch 50 secured to the back wall 40:! by rivets or by other suitable means (not shown). A pin 52 is supported by its ends in slots 44 and 46. The major axial length of pin 52 is of a size to fit slidably within the larger slot 44. However, one end 52a of the pin 52 is of reduced diameter to fit slidably within slot 46 and is thus retained within the insert 40 by reason of the cooperation between the shoulder thus formed on the pin and the rim of the slot 46. An elongated metal pawl 54 is rotatably suspended from the pin 52 and lies. within the retaining groove 48. The end of pawl 54 farthest from pin 52 includes a step 540 and an adjoining inclined end surface 5412. A lateral projection 56 carried by pawl 54 terminates in an elongated S-shaped trigger 58 displaced from pawl 54 and having its major surface perpendicular to the plane of the pawl 54. A coiled mounted portion of a stressed torsion spring 60 encircles the pin 52. A relatively short end 62 of the spring 60 extends upwardly against the end Wall 40b. A long end 64 of spring 60 extends downwardly and lies against the S shaped trigger 58 which tends to rotate the pawl 54 in a clockwise direction as viewed in FIGS. 3 and 4.

The operation of the connector of this invention will be best understood by reference to FIGS. 3 and 4. FIG. 3 illustrates the beginning of the operating cycle. The cap 10 and body 12 are axially aligned and longitudinally advanced together, the male contact blades 24 being inserted into the corresponding slots 25 of front wall 30. Initially, electrical contact is made between the male contact blades 24 and the female contacts 38. As a contact 24 is inserted into a slot 25, its end engages the upper curved leg 58 of the S-shaped. trigger 58. It will be noted that the trigger 58 is positioned at the outset generally to the right of the contact blade 24 by reason of the step 54a originally being in a latched position behind the catch 50. As the cap It is advanced toward body 12, the pawl 54 is raised by reason of the force of the end of male contact blade 24 exerted on trigger 58. This forces the ends of pin 52 to slide upwardly in the slots 44, 46 against the force exerted by the short end 62 of spring 60. This upward movement of the pawl 54 lifts the step 54a upwardly out of contact with the catch 50, as illustrated by the dashed dotted lines of FIG. 4.

It should be noted that the upper leg 58' of the S-sh-aped trigger 58 is positioned axially inwardly from the front wall 30 a distance sufficient for the locking shoulder 28 on contact leg 24 to clear the inner surface of the front wall 30 when step 54a clears the catch 50. Disengagement of the step from the catch releases the stored energy of spring 60, originally created by its stressed mounting. The force exerted by the spring 60 against the pawl 54 causes the pawl to rotate in a clockwise direction, thereby forcing the male contact blades 24 shown in FIGS. 3 and 4 to move in a clockwise direction relative to the advancing cap 10. This rotates all the contact blades relative to corresponding female contacts 38 and into .a locking relationship with body 12, shoulders 28 being positioned behind the front wall 30. This is the locked condition illustrated in FIG. 4.

it will be apparent that locking of this device takes place by merely moving the cap and body together with a force sufiicient to actuate and release the pawl 54. Manual twisting is not required to lock the parts together, as this automatically occurs on sufficient insertion of the male contact blades.

To separate the cap 10 from the body 12, it is merely necessary to manually rotate the cap 10 counterclockwise relative to its original direction of advance. This causes the contact blade 24 shown in FIG. 4 to move to the right retracting the trigger 58 and pawl 54 to the right until the inclined end surface 54b of pawl 54 contacts and rides across the inclined surface of catch 50 allowing the step 54a to ultimately clear the catch and move into its original latched position. The cap 10 may then be withdrawn from the body 12.

It is possible that, under certain circumstances of use, the pawl 54 may become unlatched while the cap 10 and body 12 are disconnected. This could occur for example, by the insertion of some object into a slot 25 in front wall 30 and releasing the pawl 54 in the same manner as a male contact blade normally should. For this reason, the lower leg 58" is provided on the S-shaped trigger 58. As will be seen from FIG. 4, when the pawl 54 is in the unlatched position, the lower leg 58" of trigger 58 slopes downwardly with a relatively sharp angle. Accordingly, the insertion of a male contact blade into a slot in end wall 30 under such conditions will initially cause the trigger 58 and pawl 54 to be cammed to the right and int-o the latching position to cock it for its normal locking function.

The many advantages of this invention will be readily appreciated by those skilled in the art. It will be noted that the male contact blades do not norm-ally engage the locking means actuator, viz, trigger 58, until they are near the end of their longitudinal travel; therefore, connection of the cap to the body is easily effected. It will be further noted that the individual locking inserts are unit handled and may be added to existing conventional interlocking connectors to render them automatically interlocking. It will also be noted, for example, that the inserts automatically adjust to the alignments and tolerances of the male contacts blades. It will be understood that a number of variations and modifications may be made in this invention without departing from the spirit and scope thereof. Accordingly, the foregoing description should be construed as illustrative only rather than limiting. This invention is limited only by the scope of the following claims.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. An interlocking electrical connector which comprises: a body portion of electrical insulating material defining therein a plurality of circularly positioned chambers; a front wall on said body defining a plurality of spaced openings, each of said openings communicating with a different one of said chambers; female electrical contact means within each of said chambers positioned to receive a male contact blade inserted longitudinally through the corresponding opening; a plurality of elongated removable support means within said body portion, each of said support means being circumferentially spaced from a corresponding female contact means; elongated pawl means on each of said support means having a first end and a second end; pivot means supporting the first end of said pawl means for allowing pivotal movement of said pawl means thereabout and longitudinal movement of said pawl means substantially parallel to the longitudinal motion of said male contact blade; means resiliently urging said pawl means longitudinally toward said slots; means resiliently urging the second end of said pawl means circumferentially toward said male contact blade; catch means on said support means arranged to engage the second end of said pawl means and latch said second end in a retracted position away from said male contact blade; and latch release means on said pawl means positioned in the path of longitudinal travel of said blade means when said pawl means is so retracted whereby continued longitudinal displacement of said blade means against said trigger means moves said pawl means l0ngitudinally and releases said pawl means from said catch means.

2. The connector of claim 1 wherein said latch release means is substantially S-shaped, a first arm of said S being positioned in said blades path of longitudinal travel when said pawl means is in a latched position and a second arm of said S forming an inclined plane in said path of longitudinal travel when released from said catch means.

3. The connector of claim 1 wherein said catch means comprises an inclined surface terminating in a latching peak and wherein the second end of said pawl means is positioned to slide along said inclined surface, in response to its circumferential displacement by a male contact blade against the resilient means urging said pawl means toward said blade, to a latching position behind said peak.

4. An insert for the connector body of an interlocking electrical connector which comprises: a generally elongated base member having a first end and a second end; bracket means on the first end of said base member, said bracket means and base member defining therein first and second spaced apart aligned oval openings, the longer dimensions of said openings being parallel to the major dimension of said base member; a pivot pin supported by and extending between said oval openings; elongated pawl means having a first end supported by said pivot pin and positioned between said openings, said pawl means extending generally parallel to said base member; inclined plane means supported at the second end of said base mem ber to engage the second end of said pawl means upon pivoting about said pilot pin, the innermost end of said inclined plane means defining a latching peak; first resilient means urging said pawl means toward the second end of said base member to selectively latch said pawl member in a latching relationship with said latching peak; second resilient means resiliently urging the second end of said pawl means pivotally outwardly from said inclined plane means upon release from said latching peak; and latch release means on said pawl means arranged to intercept a male contact blade to force said pawl member against said first resilient means to release its second end from said latching peak.

References Cited by the Examiner UNITED STATES PATENTS 712,078 10/02 Kuebler 292-335 2,787,772 4/57 Liaci 339-99 2,799,009 7/57 Benander 339-91 X 3,066,276 11/62 Hubbell et a1 339189 3,083,274 3/63 Sparkes 3399l X I OSEPH D. SEERS, Primary Examiner. W. DONALD MILLER, Examiner. 

4. AN INSERT FOR THE CONNECTOR BODY OF AN INTERLOCKING ELECTRICAL CONNECTOR WHICH COMPRISES: A GENERALLY ELONGATED BASE MEMBER HAVING A FIRST END AND A SECOND END; BRACKET MEANS ON THE FIRST END OF SAID BASE MEMBER, SAID BRACKET MEANS AND BASE MEMBER DEFINING THEREIN FIRST AND SECOND SPACED APART ALIGNED OVAL OPENINGS, THE LONGER DIMENSIONS OF SAID OPENINGS BEING PARALLEL TO THE MAJOR DIMENSION OF SAID BASE MEMBER; A PIVOT PIN SUPPORTED BY AND EXTENDING BETWEEN SAID OVAL OPENINGS; ELONGATED PAWL MEANS HAVING A FIRST END SUPPORTED BY SAID PIVOT PIN AND POSITIONED BETWEEN SAID OPENINGS, SAID PAWL MEANS EXTENDING GENERALLY PARALLEL TO SAID BASE MEMBER; INCLINED PLANE MEANS SUPPORTED AT THE SECOND END OF SAID BASE MEMBER TO ENGAGE THE SECOND END OF SAID PAWL MEANS UPON PIVOTING ABOUT SAID PILOT PIN, THE INNERMOST END OF SAID INCLINED PLANE MEANS DEFINING A LATCHING PEAK; FIRST RESILIENT MEANS URGING SAID PAWL MEANS TOWARD THE SECOND END OF SAID BASE MEMBER TO SELECTIVELY LATCH SAID PAWL MEMBER IN A LATCHING RELATIONSHIP WITH SAID LATCHING PEAK; SECOND RESILIENT MEANS RESILIENTLY URGING THE SECOND END OF SAID PAWL MEANS PIVOTALLY OUTWARDLY FROM SAID INCLINED PLANE MEANS UPON RELEASE FROM SAID LATCHING PEAK; AND LATCH RELEASE MEANS ON SAID PAWL MEANS ARRANGED TO INTERCEPT A MALE CONTACT BLADE TO FORCE SAID PAWL MEMBER AGAINST SAID FIRST RESILIENT MEANS TO RELEASE ITS SECOND END FROM SAID LATCHING PEAK. 